Mn(III)-based radical addition reactions of 2-nitroindole with activated CH compounds

2-Nitroindole undergoes addition reactions with the radicals generated from active CH compounds upon treatment with Mn(OAc)3·2H2O to afford the corresponding 3-substituted-2-nitroindoles in 27–66% yields. Products of the methylene addition reactions undergo a subsequent in situ Nef reaction to afford 2-oxoindolin-3-ylidenes.